The ErbB/HER family of growth factor receptors plays an important role in cell signaling during development and proliferation. Several ErbB/HER family members are associated with human diseases, including, for example, cancer. Numerous ligands which bind and activate ErbB/HER receptors have been identified, including epidermal growth factor (EGF), epiregulin, amphiregulin and members of the neuregulin family (Ben-Baruch et al., Hormones and growth factors in development and neoplasia. Dickson R B and Salomon D S (eds). Kulwer Academic Publishers: Boston, pp. 145-168, 1988; Burden and Yarden, Neuron 18:847-855). Because signal transduction pathways involving ErbB/HER family members are associated with human disease, there is a need in the art for ligands which signal through these receptors. The ligand proteins and the genes encoding them are useful for therapeutic purposes.
This invention provides a gene of the neuregulin family and polypeptides encoded by the gene. The invention is directed to mRNA expressed by mammalian cells, polynucleotides having coding regions corresponding to the mRNAs, protein and polypeptide products of the polynucleotides and mRNAs, and biological functions of the polypeptides and proteins.